This invention relates to reconstituted body fluids having leukocyte simulating particles dispersed therein and a method for producing same.
In carrying out the clinical examination of various body fluids, such as for example, blood, urine, spinal fluid and the like, it is standard practice to utilize a known sample of the body fluid as a standard for determining the quantity of the constituent being tested for and for quality control purposes to test the accuracy of the procedure. For this purpose standard body fluid samples containing precise levels of key constituents are prepared on a commercial basis. For the purpose of increasing the stability and shelf life, the commercially available standard body fluids are normally supplied in the lyophilized form and are reconstituted by the addition of water immediately prior to use. Accordingly such commercially prepared standard fluids are referred to herein as reconstituted body fluids.
An important constituent of body fluids insofar as diagnostic techniques are concerned are white cells or leukocytes. Depending on the particular body fluid being examined, the presence or absence of leukocytes and the number of leukocytes if present provide important diagnostic information on the condition of the patient and a standard sample of body fluid should advantageously include a known value of leukocytes.
Leukocytes, however, have a relatively short life in vitro, normally on the order of 18 to 30 hours. Consequently, in the commercially available reconstituted body fluids, known amounts of particles are introduced as a substitute for the leukocytes which, as mentioned before, have a relatively short in vitro existence. Such particles have included polystyrene latex spheres, butadiene spheres, polyvinyltuoluene spheres, silica, kaolin and the like which are prepared to particle size so as to resemble a leukocyte. Such particles, however, are readily distinguished from leukocytes and, accordingly, reconstituted body fluids utilizing such particles in the place of leukocytes are readily detected by the technician and detract from the use of the body fluid as a hidden sample for quality control purposes. In addition, such particles resemble leukocytes in size only but not in appearance and therefor detract from the use of the reconstituted body fluid as a teaching tool to aid new technicians in recognizing leukocytes in body fluids.
The reconstituted body fluids of the present invention overcome the foregoing deficiencies in prior art reconstituted fluids and therefore, are advantageously utilized both as a quality control tool in the clinical examination of body fluids and as a teaching vehicle to aid new technicians in the handling and recognition of leukocytes in body fluids.